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==Crystal structure of helicase Pif1 from Thermus oshimai mutant Q164C-E409C==
<StructureSection load='7ada' size='340' side='right'caption='[[7ada]], [[Resolution|resolution]] 3.34&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=7ADA OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=7ADA FirstGlance]. <br>
</td></tr><tr id='method'><td class="sblockLbl"><b>[[Empirical_models|Method:]]</b></td><td class="sblockDat" id="methodDat">X-ray diffraction, [[Resolution|Resolution]] 3.34&#8491;</td></tr>
<tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[https://proteopedia.org/fgij/fg.htm?mol=7ada FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=7ada OCA], [https://pdbe.org/7ada PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=7ada RCSB], [https://www.ebi.ac.uk/pdbsum/7ada PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=7ada ProSAT]</span></td></tr>
</table>
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== Publication Abstract from PubMed ==
Pif1 is an SF1B helicase that is evolutionarily conserved from bacteria to humans and plays multiple roles in maintaining genome stability in both nucleus and mitochondria. Though highly conserved, Pif1 family harbors a large mechanistic diversity. Here, we report crystal structures of Thermus oshimai Pif1 (ToPif1) alone and complexed with partial duplex or single-stranded DNA. In the apo state and in complex with a partial duplex DNA, ToPif1 is monomeric with its domain 2B/loop3 adopting a closed and an open conformation, respectively. When complexed with a single-stranded DNA, ToPif1 forms a stable dimer with domain 2B/loop3 shifting to a more open conformation. Single-molecule and biochemical assays show that domain 2B/loop3 switches repetitively between the closed and open conformations when a ToPif1 monomer unwinds DNA and, in contrast with other typical dimeric SF1A helicases, dimerization has an inhibitory effect on its helicase activity. This mechanism is not general for all Pif1 helicases but illustrates the diversity of regulation mechanisms among different helicases. It also raises the possibility that although dimerization results in activation for SF1A helicases, it may lead to inhibition for some of the other uncharacterized SF1B helicases, an interesting subject warranting further studies.

Structural and functional studies of SF1B Pif1 from Thermus oshimai reveal dimerization-induced helicase inhibition.,Dai YX, Chen WF, Liu NN, Teng FY, Guo HL, Hou XM, Dou SX, Rety S, Xi XG Nucleic Acids Res. 2021 Mar 30. pii: 6204648. doi: 10.1093/nar/gkab188. PMID:33784404<ref>PMID:33784404</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
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==See Also==
*[[Helicase 3D structures|Helicase 3D structures]]
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Large Structures]]
[[Category: Chen WF]]
[[Category: Dai YX]]
[[Category: Dou SX]]
[[Category: Hou XM]]
[[Category: Liu NN]]
[[Category: Rety S]]
[[Category: Teng FY]]
[[Category: Xi XG]]